Derby’s Bradley Johnson attempted to bite Stoke City rival Joe Allen during a large-scale melee during the Championship showdown.
The pair scuffled after Peter Etebo's reckless studs-up challenge on Richard Keogh earned the Stoke player a red card on a heated night at the Bet365 Stadium, with the home team coming out 2-1 winners.
In the aftermath of Etebo's foul, Bradley and Allen tangled with the former lunging at the latter with his teeth, though TV replays suggested he may have only got a mouthful of his opponent's shirt.
He escaped with a yellow card and Derby manager Frank Lampard replaced him with Tom Huddlestone at half-time.
Stoke boss Gary Rowett, in charge of Derby last season, attempted to play down the incident with his former player - though Johnson could still face action if the FA deemed it worthy of further investigation.
Rowett said: "We are not going to make any complaints. I spoke to Joe and he said it wasn’t anything massively problematic.
"It was part of the melee, a moment in the game that probably looked worse than it was."
Rowett quit Derby to join Stoke six months ago and the travelling support taunted him with chants and inflatable snakes.
"It took a lot of discipline and great determination to win with 10 men," said Rowett. "That was the biggest performance of our season. We didn’t crumble. I’m taking one of those snakes home with me!"
Goals from Sam Clucas and Tom Ince gave Stoke the win. Harry Wilson scored for Derby.
His first-half hat-trick made it 3-3 at the break after the visitors had led 2-0 and 3-2 through Lewis Grabban, Joao Carvalho and Matthew Cash.
Joe Lolley restored their lead before Abraham, on loan from Chelsea, added another to draw level again.
Villa then took their first lead at 5-4 when Anwar El Ghazi scored but Grabban struck again to earn the draw.